1. Field
One or more embodiments of the present invention relate to an oil-water separation structure having a nano-patterned structure on a surface thereof, a method of manufacturing the oil-water separation structure, an oil-water separator including the oil-water separation structure, and an oil-water separation method using the oil-water separator.
2. Description of the Related Art
Technology for removing oil spilled in the sea or the river includes adjusting surface energy, such as hydrophilicity and hydrophobicity of a surface of a separator to separate and remove oil that was spilled from the water.
Technology for separating oil and water (hereinafter, oil-water separation technology) may be largely categorized into two groups. The first group involves using a superoleophilic and superhydrophobic filter having low surface energy, which lets oil flow out but prevents water from flowing out, and the second group involves using an hydrophilic or superhydrophilic filter having high surface energy, which lets water flow out but prevents oil from flowing out due to a water membrane formed on the filter. To selectively separate and retrieve oil from a mixture of oil and water, a filter that operates based on the second technology may be more useful. In this regard, technology for hydrophilizing the filter is needed.
As a method of forming a hydrophilic or superhydrophilic surface on a surface of a material, wet etching, UV treatment, plasma/ion treatment, or the like may be used. More particularly, it is known that when a material having an increased surface roughness and hydrophilicity is used to control chemical properties of the surface, a hydrophilic or superhydrophilic surface may be obtained.
However, despite efforts to achieve hydrophilic properties on surfaces of various materials and thin films, the hydrophilicity of a surface of a general material disappears easily over time. This is because water molecules or fine particles such as or hydrocarbons in the air tend to easily bind to a hydrophilic surface due to relatively high surface energy of the hydrophilic surface, in order to decrease surface energy of the hydrophilic surface, and as a result of such binding, surface energy of the hydrophilic surface decreases and the hydrophilic surface loses hydrophilicity. Effects obtained from most hydrophilic or superhydrophilic treatments known in the art are lost within a few hours or a few days, and thus, lots of research into developing a surface that retains hydrophilicity or superhydrophilicity for a longer time is under progress. Also, manufacturing the hydrophilic or superhydrophilic surface into large surface area and mass production for manufacturing the hydrophilic or superhydrophilic surface are required.
As environmental problems are being raised due to the sophistication of industries, research into materials for separating and/or removing specific materials from mixtures, such as oil-water separator and seawater desalinating apparatus, are continually increasing. Also, lots of research is under progress for developing an oil-water separation method in which when an oil spillage accident occurs, crude oil is primarily retrieved, the retrieved crude oil may be reused, and secondary environmental pollution is not induced during the retrieval process.
Accordingly, an oil-water separation structure having a large surface area, for which a manufacturing process thereof is environmentally friendly and a durability of the structure is excellent, is needed.